Over the past thirty years, there has been extensive research conducted on the role hydration and carbohydrate supplementation play in improving exercise performance. This research led to the development of sports drinks that contain carbohydrate in the range of 6-8%, as well as essential electrolytes such as sodium, potassium, magnesium and chloride. Numerous studies have shown that consumption of a sports drink during exercise containing carbohydrate and electrolytes enables athletes to extend their endurance capacity to a greater extent than by the consumption of water alone.
When a sports drink is consumed during exercise, the carbohydrate is transported from the blood into the muscle where it then can be converted into energy. Normally, glucose uptake is controlled by insulin. However, during periods of intense activity, there is a decrease in the production of insulin and glucose is transported into the muscle primarily by the contraction of the muscle cell. The uptake of glucose into the muscle is critical to preserve muscle glycogen. To the degree that muscle glycogen is preserved, there is an enhancement in endurance capacity since more muscle glycogen is then available in the later stages of exercise.
The concentration of carbohydrate in the plasma is critical in determining the amount available for transport into the muscle cell and use in energy contraction. The levels of carbohydrate in the plasma are in large part controlled by the amount of carbohydrate that is absorbed into the plasma from the GI tract and the amount of carbohydrate that is transported into the muscle. Carbohydrate is transported from the gut to the plasma via multiple pathways. There is a specific transport pathway for glucose, a simple sugar, a specific transport pathway for fructose, another type of simple sugar, and a third transport pathway for disaccharides such as sucrose. Most sports drinks contain predominantly one type of sugar, either sucrose or fructose. A sports drink that contains predominantly one type of sugar is not as effective in extending endurance. The reason is a sports drink that contains primarily one type of sugar will overwhelm the transporter system. If the drink contains primarily fructose it will overwhelm the fructose transporter system. If it contains primarily glucose it will overwhelm the glucose transporter system. This can have a negative impact on the effectiveness of the sports drink since, if less carbohydrate can be transported from the gut to the plasma then less carbohydrate will be available in the plasma for transport into the blood. When the amount of carbohydrate in the plasma becomes rate limiting muscle cells increase their utilization of their own carbohydrate source called glycogen.
The faster that muscle glycogen is depleted the faster that muscle fatigue ensues and endurance is decreased.
The transport of carbohydrate from the plasma into the muscle cell is largely controlled by insulin and different carbohydrate transporters than that seen in the gut but which have a similar function. It has been shown that when insulin is stimulated during intense exercise there is a greater uptake of glucose. Increasing carbohydrate consumption during exercise can stimulate insulin to a point. When very high levels of carbohydrate are consumed during exercise they do not empty from the stomach rapidly so carbohydrate intake becomes rate limiting in its ability to stimulate insulin.
Previously, it has been shown that when protein is added to a source of carbohydrate, it can provide enhanced stimulation of insulin. The level of protein is critical since protein has been shown to slow gastric emptying. U.S. Pat. No. 6,207,638 showed that when protein is added to carbohydrate in a 4 to 1 ratio, it provides increased insulin stimulation and enhances the synthesis of muscle glycogen with no negative impact on rehydration following exercise. In addition to stimulating insulin to improve carbohydrate uptake, a second but important benefit of using a combination of carbohydrates that have specific transport systems is a more rapid uptake of carbohydrate into the muscle.
There is a definite need in the art for sports drinks that will maximize the uptake of glucose during exercise, thereby providing an immediate source of energy and improve endurance by the sparing of muscle glocogen stores. It is the object of this invention to provide a sports drink that will improve athletic performance during exercise.